| 摘要 |
PURPOSE:To exchange data among other plural transmission and reception circuits even at power interruption of one transmission and reception circuit by providing a connecting diode to a data line and a transistor (TR) for data transmission and reception, in each electric device. CONSTITUTION:In a system where a data transmission and reception circuit 5 transmitting and receiving data for control provided respectively in plural electric devices 1 is connected by the data line 9 and data are exchanged mutually among the devices 1, the diode D1 connecting a data from the transmission and reception circuit 5 to the line 9 without attenuation and a TRQ1 fetching a data from other transmission and reception circuit 5 to which the data is applied via the line 9 with a very high input impedance from the line 9 at application and interruption of power of the transmission and reception circuit 5 are provided in each device 1. As a result, even if the power to any transmission and reception circuit 5 is interrupted, the data is exchanged among the plural transmission and reception circuits 5 to which the power is supplied. |
